[Illuminated One]

What many people don't understand about the AI is that it's quite depressed.
Whenever preparing a battle you must plan ahead and take away any opportunities to commit suicide or kill their friends from your mages.

Planning to use lightning damage? Do not have ironskin researched. Or cast it yourself followed by lightning resistance and a lightning resistance ring.
Enemy has fire mages? Let your nature mages lead the charge instead of casting mass protection.
Now, the AI has not yet figured out how to kill itself with a sword, so SCs are fine.